Tungsten arc lamp



. current.

Patented Sept. 21, 1926.

meassz UNITED STATES PAT Nr orrics.

FRITZ BAHR, OF BERLm-CHARLOTTENBURG, GERMANY, .A SSIGNOB TO GENERALELECTRIC COMPANY, CORPORATION OF NEW YORK.

TUNos'rnn ABC AMP.

Application flled May 14, 1924, Serial No.

My invention relates to tungsten are lamps in which the are is startedby separating the electrodes. More in particular the invention relatesto that type of tungsten arc in which a bimetallic strip is used tocause the separation of the electrodes. In tungsten lamps of theforegoing character, strips of this sort are connected in thesupportingstem of the anode in the circuit over which the current passes andconsequently become heated by the flow of the current. The tungstenelectrode is so connected to the bimetallic strip and the strip soarranged;

that when the bimetallicstrip bends the anode is separated from thecathode and the arc is established. It frequently occurs, when the usualform of bimetallic strip is used, that sufficient distortion does nottake place to separate the electrodes when the current is turned on.This is especially the case in lamps that use a small amount of One ofthe objects of my invention is to provide a bimetallic strip ofsuch'construd' tion as to insure a suflicient degree of bend-, ing andthereby insure a more reliable opera-' tion of the lamp even when asmall amount of current is used. This is accomplished, for. example, byincreasing the length of the path of the current over the bimetallicelement by making the element in a zigzag form. It is. also an object toprovide an improved arrangement for increasing the stability of thesupporting wire stemby holding the loops of the bimetallic striptogether with one or more clamps of suitable insulating material.

. To accomplish the foregoing, I make use of means hereinafter morefully set' forth and claimed, reference belng had to the accompanvingdrawing.

1 n Fig.1 of the drawing-,thereis shown one example of construction of atupgst n lamp made in accordance with th'eprincipleu of my invention; inFig. 2 the biinet'allic'element is :zliOWll in Side "iew, and inFig. 3the bimctall ic strip is shown in a position similar to that of Fig.2'with the supporting clamps, one at i he upper endand .one at the lowerend.

Referring more in detail to the drawing, it will be seen that the lampcomprises a glass envelope a similar to that used in the ordinaryincandescent lamp. The lamp also the lamp is not in use.

' zigzag strips 9 .folded 713,361, and in Germany August 4, 1923.

comprises a screw base'b and a glass stem 0 through which stem theleading-in wires d pass that formv the supporting stems e of the twoelectrodes f that restin contact when Into the supporting stem of theanode is inserted the bi-metallic at the points 9 as shown. The loops gof the bimetallic strip are clearly shown in Fig. 2.

- The folds of the bimetallic strips are supported on the sides bysuitable insulating plates k of mica, for example, which may e clampedinto position in any suitable manner. VVit-h thisarrangement the loopsor the strip are given greater stability.

I have shown in the drawing a bimetallic stood hpwever that a similarbimetallic strip may be lnsert-ed ineach one of the wire stems.Furthermore, if the lamp is provided with two electrodes, at bimetallicstrip may be provided for each electrode.

strip' in the anode stem. It will be underhave shown and describedspecific embodiments of my invention, 1 do not wish to be limited tothese specific constructions inas much as other variations will readilysug-- gest themselves which may be made without departing from thespirit of my invention and without departing from the scope of myclaims. J

hat I claim as new and desire to secure by Letters Patent of the UnitedStates, is,-

1. An arc lamp provided with a bimetallic element for separating, oneofthe electrodes trom .another when an electric current is sent throughthe element, said element being folded into a plurality of loops andmeans for reinforcing the folds of the .element.

An are lamp provided with a bimetallic element for'separating one ofthe' electrodes from another when an electric current is sent throughthe element, said element being folded intoa plurality of loops, andmeans for holding the .folds of the element in alignment.

In witness whereof, I have hereunto set my hand this 16th day of April,1924.

FRITZ

